System and method of mimetic messaging settings selection

ABSTRACT

Systems and methods of mimetic message settings selection on a messaging client are provided. In one embodiment, when an outgoing message is composed on a messaging client, the messaging client determines whether the outgoing message is related to a received message. Where the outgoing message is related to the received message, the messaging client determines the messaging settings used in the received message, and selects the messaging settings used in the received message to control message characteristics of the outgoing message.

TECHNICAL FIELD

This invention relates generally to the field of electronic messaging,and in particular to selecting messaging settings to control messagecharacteristics on a messaging client.

BACKGROUND ART

Known electronic messaging software clients (“messaging clients”), suchas e-mail software applications operating on desktop computer systems,can use only one set of messaging settings at a time. Messaging settingsmay be established, using a mouse, a keyboard or another input devicefor example, to control such message characteristics as formats, fonts,and common text that should appear in all outgoing messages, as well assecure messaging characteristics such as message signing, encryption,and steganography, including message hiding and other obfuscationschemes, for example. Although a user may establish more than one groupof settings, only one group, previously selected as current or defaultsettings, controls messaging operations on a messaging client at anytime. In order to configure different message characteristics than thoseestablished in the current settings for an outgoing message, the currentsettings must be over-ridden or another group of settings must beselected. These operations may be cumbersome, particularly when messagecharacteristics must be changed frequently, when the addressees ofoutgoing messages have different messaging capabilities, or whendifferent messaging settings should be used for different types ofmessages, for example.

DISCLOSURE OF INVENTION

According to an aspect of the invention, a method of mimetic messagesettings selection on a messaging client comprises the steps ofdetecting an outgoing message, determining whether the outgoing messageis related to a previously received message, the received message havingmessage characteristics, determining messaging settings associated withthe message characteristics of the received message where the outgoingmessage is related to a previously received message, and selecting themessaging settings associated with the message characteristics of thereceived message to control message characteristics of the outgoingmessage.

In accordance with another aspect of the invention, a system of mimeticmessaging settings selection comprises a message store configured tostore messages having message characteristics and a messaging client.The messaging client is configured to determine whether an outgoingmessage to be sent is related to a message in the message store, todetermine messaging settings associated with the message characteristicsof the message in the message store where the outgoing message isrelated to a message in the message store, and to select the messagingsettings associated with the message characteristics of the message inthe message store to control message characteristics of the outgoingmessage.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of an exemplary messaging system.

FIG. 2 is a block diagram illustrating a secure e-mail message exchangein a messaging system.

FIG. 3 is a block diagram of a wireless mobile communication deviceimplementing a mimetic messaging settings selection system.

FIG. 4 is a block diagram showing an exemplary message structure thatsupports mimetic messaging settings selection.

FIG. 5 is a flow chart illustrating a method of mimetic messagingsettings selection.

FIG. 6 is a block diagram of a wireless mobile communication device.

BEST MODE FOR CARRYING OUT THE INVENTION

Messaging settings may control general message characteristics such asmessage format and fonts for both unsecure messages and secure messages.Unsecure messages include, for example, classical e-mail messages thatare exchanged between messaging clients through the Internet. Securemessage characteristics such as message signing and encryption may alsobe controlled by establishing messaging settings. A secure message maybe signed with a digital signature, encrypted, or both, and possiblyalso be processed in other ways by a messaging client operating on or inconjunction with a message sender system or intermediate system betweena message sender system and a receiving messaging client which receivesthe secure message. For example, a secure message may be a message thathas been encrypted, signed, encrypted and then signed, or signed andthen encrypted by a sending messaging client according to variants ofSecure Multipurpose Internet Mail Extensions (S/MIME). A secure messagecould similarly be encoded, compressed or otherwise processed eitherbefore or after being signed and/or encrypted. Thus, messaging settingsmay include general messaging settings, secure messaging settings orboth.

A messaging client allows a system on which it operates to receive andpossibly also send messages. Messaging clients may operate on a computersystem, a handheld device, or any other system or device withcommunications capabilities. Many messaging clients also have additionalnon-messaging functions.

FIG. 1 is a block diagram of an exemplary messaging system.. The system10 includes a Wide Area Network (WAN) 12, coupled to a computer system14, a wireless network gateway 16, and a corporate Local Area Network(LAN) 18. The wireless network gateway 16 is also coupled to a wirelesscommunication network 20, in which a wireless mobile communicationdevice 22 (“mobile device”) is configured to operate.

The computer system 14 may be a desktop or laptop personal computer(PC), which is configured to communicate to the WAN 12, which may be theInternet. PCs, such as computer system 14, normally access the Internetthrough an Internet Service Provider (ISP), an Application ServiceProvider (ASP), or the like.

The corporate LAN 18 is an example of a network-based system in which amessaging client may operate. It is normally located behind a securityfirewall 24. Within the corporate LAN 30, a message server 26, operatingon a computer behind the firewall 24, serves as the primary interfacefor the corporation to exchange messages both within the LAN 18, andwith other external messaging clients via the WAN 12. Two known messageservers 26 are Microsoft™ Exchange server and Lotus Domino™ server.These servers 26 are often used in conjunction with Internet mailrouters to route and deliver mail messages. The message server 26 mayalso provide additional functionality, such as dynamic database storagefor calendars, todo lists, task lists, e-mail, electronic documentation,and the like.

The message server 26 provides messaging capabilities to thecorporation's networked computer systems 28 coupled to the LAN 18. Atypical LAN 18 includes multiple computer systems 28, each of whichimplements a messaging client, such as Microsoft Outlook™ or LotusNotes, for example. Within the LAN 18, messages are received by themessage server 26, distributed to the appropriate mailboxes for useraccounts addressed in the received messages, and are then accessed by auser through a computer system 28 on which a messaging client isoperating.

The wireless network gateway 16 provides an interface to a wirelessnetwork 20, through which messages may be exchanged with a mobile device22. Such functions as addressing of the mobile device 22, encoding orotherwise transforming messages for wireless transmission, and any otherrequired interface functions may be performed by the wireless gateway16. The wireless network gateway 16 may be configured to operate withmore than one wireless network 20, in which case the wireless networkgateway 16 may also determine a most likely network for locating a givenmobile device and track mobile devices as they roam between countries ornetworks.

Any computer system 14, 28 with access to the WAN 12 may exchangemessages with a mobile device 22 through the wireless network gateway16. Alternatively, private wireless network gateways, such as wirelessVirtual Private Network (VPN) routers could also be implemented toprovide a private interface to a wireless network. For example, awireless VPN implemented in the LAN 18 provides a private interface fromthe LAN 18 to one or more mobile devices 22 through the wireless network20. Such a private interface to mobile devices 22 via the wirelessnetwork gateway 16 and/or the wireless network 20 may also effectivelybe extended to entities outside the LAN 18 by providing a messageforwarding or redirection system that operates with the message server26. Such a redirection system is disclosed in United States Patent No.6,219,694, which is hereby incorporated into this application byreference. In this type of redirection system, incoming messagesreceived by the message server 26 and addressed to an account or mailboxassociated with a user of a mobile device 22 are sent through thewireless network interface, either a wireless VPN router, the wirelessnetwork gateway 16 or some other interface, to the wireless network 20and to the user's mobile device 22. Another alternate interface to auser's mailbox on a message server 26 may be a Wireless ApplicationProtocol (WAP) gateway. Through a WAP gateway, a list of messages in auser's mailbox on the message server 26, and possibly each message or aportion of each message, could be sent to the mobile device 22.

A wireless network 20 normally delivers messages to and from mobiledevices 22 via RF transmissions between base stations and mobile devices22. The wireless network 20 may, for example, be: (1) a data-centricwireless network, (2) a voice-centric wireless network, or (3) adual-mode network that can support both voice and data communicationsover the same infrastructure. Recently developed wireless networksinclude: (1) the Code Division Multiple Access (CDMA) network, (2) theGroupe Special Mobile or the Global System for Mobile Communications(GSM) and the General Packet Radio Service (GPRS) networks, and (3)third-generation (3G) networks, such as Enhanced Data rates for GlobalEvolution (EDGE) and Universal Mobile Telecommunications Systems (UMTS).Examples of data-centric network include: (1) the Mobitex™ Radio Network(“Mobitex”), and (2) the DataTAC™ Radio Network (“DataTAC”). Knownvoice-centric networks include Personal Communication Systems (PCS)networks like GSM and Time Division Multiple Access (TDMA) systems.

The mobile device 22 may be a data communication device, a voicecommunication device, or a multiple-mode device capable of voice, dataand other types of communications. An exemplary mobile device isdescribed in further detail below, in conjunction with FIG. 6.

Perhaps the most common type of messaging currently in use is e-mail. Ina standard e-mail system, an e-mail message is sent by an e-mail sender,possibly through a message server and/or a service provider system, andmay then be routed through the Internet to one or more messagereceivers. E-mail messages are normally sent in the clear and typicallyuse Simple Mail Transfer Protocol (SMTP) headers and Multi-purposeInternet Mail Extensions (MIME) body parts to define the format of thee-mail message.

In recent years, secure messaging techniques have evolved to protectboth the content and integrity of messages, such as e-mail messages.S/MIME and Pretty Good PrivaCy™ (PGP™) are two public key secure e-mailmessaging protocols that provide for both encryption, to provide messageconfidentiality, and signing, which protects the integrity of a messageand provides for sender authentication by a message receiver. Inaddition to utilizing digital signatures and possibly encryption, securemessages may also or instead be encoded, compressed or otherwiseprocessed. Other secure messaging schemes, including OpenPGP and GnuPrivacy Guard (GPG) for example, may also be apparent to those skilledin the art to which the present application relates. The systems andmethods described herein may be implemented in conjunction with theseand other known secure messaging schemes, as well as future securemessaging schemes.

FIG. 2 is a block diagram illustrating a secure e-mail message exchangein a messaging system. The system includes an e-mail sender system 30,coupled to a WAN 32, and a wireless network gateway 34, which providesan interface between the WAN 32 and a wireless network 36. A mobiledevice 38 is adapted to operate within the wireless network 36.

The e-mail sender system 30 may be a PC, such as the computer system 14in FIG. 1, or it may be a network-connected computer, such as computer28 in FIG. 1, on which a messaging client is operating. The e-mailsender system 30 may also be a mobile device on which a messaging clientoperates to enable e-mail messages to be composed and sent. The WAN 32,the wireless network gateway 34, the wireless network 36 and the mobiledevice 38 are substantially the same as similarly-labelled components inFIG. 1.

The example secure e-mail message 40 sent by the e-mail sender 30includes a component 42 including the sender's Cert, Cert chain, CRLsand digital signature and the signed message body 44. In the S/MIMEsecure messaging technique, Certs, CRLs and digital signatures arenormally placed at the beginning of a message as shown in FIG. 2, andthe message body is included in a file attachment. Messages generated byother secure messaging schemes may place message components in adifferent order than shown or include additional and/or differentcomponents. For example, a signed message may include addressinginformation, such as “To:” and “From:” email addresses, and other headerinformation.

When the secure e-mail message 40 is sent from the e-mail sender system30, it is routed through the WAN 32 to the wireless network gateway 34.Although the e-mail sender system 30 sends the message 40 directly tothe wireless network gateway 34, in an alternative implementation themessage is instead delivered to a computer system associated with themobile device 38 and then sent to the mobile device 38 by the associatedcomputer system. As described above, in a further alternativeembodiment, the message is routed or redirected to the mobile device 38through the wireless network 36 via a wireless VPN router or otherinterface.

The receiver of the signed message 40, the mobile device 38, checks thedigital signature 42 using the sender's signature public key (in apublic key signature scheme) and a signature verification algorithmcorresponding to the signature algorithm used at the sender system 30.If the secure message 40 was encrypted or otherwise processed at thesender system 30 after being signed, then the mobile device 38 firstdecrypts or performs other inverse processing operations on the messagebefore signature verification is performed. If encryption or processingwas performed before signing, however, inverse processing such asdecryption is performed after signature verification.

In order to verify the digest signature, the receiver 38 retrieves thesignature public key of the sender, generally by extracting the publickey from the sender's Cert 42 attached to the message 40, and thenperforms the signature verification algorithm using the retrieved publickey. The secure message 40 shown in FIG. 2 includes the sender's Cert42, from which the sender's public key can be extracted. The sender'spublic key may also be retrieved from a local store, for example wherethe public key was extracted from an earlier message received from thesender and stored in a key store in the receiver's local store.Alternatively, the public key may be retrieved from the sender's Certstored in a local store, or from a Public Key Server (PKS). A PKS is aserver that is normally associated with a Certificate Authority (CA)from which a Cert for an entity, including the entity's public key, isavailable. A PKS might reside within a corporate LAN such as 18 (FIG.1), or anywhere on the WAN 32, the Internet or any other network orsystem through which message receivers may establish communications withthe PKS.

The Cert, Cert chain and CRLs 42 are used by a receiver to ensure thatthe sender's Cert is valid, i.e., that the Cert has not been revoked orexpired, and is trusted. A Cert is often part of a Cert chain, whichincludes a user's Cert as well as other Certs to verify that the user'sCert is authentic. For example, a Cert for any particular entitytypically includes the entity's public key and identificationinformation that is bound to the public key with a digital signature.Several types of Cert currently in use include, for example, X.509Certs, which are typically used in S/MIME, and PGP Certs, which have aslightly different format. In S/MIME, the digital signature in a Cert isgenerated by the issuer of the Cert, and can be checked by a messagereceiver as described above. A Cert may include an expiry time orvalidity period from which a messaging client may determine if the Certhas expired. Each Cert may also be checked against a CRL to ensure thatthe Cert has not been revoked.

If the digital signature in a message sender's Cert is verified, theCert has not expired or been revoked and the issuer of the Cert istrusted by a message receiver, then the digital signature of the messageis trusted by the message receiver. If the issuer of the Cert is nottrusted by the receiver, then the message receiver may trace acertification path through the Cert chain to verify that each Cert inthe chain was signed by its issuer, whose Colt is next in the Certchain, until a Cert is found that was signed by a root Cert from asource trusted by the receiver, such as from a large PKS. Once a rootCert is found, then a signature can be trusted, because both the senderand receiver trust the source of the root Cert. This trust mechanism isused, for example, in S/MIME. Although other messaging schemes,including PGP, for example, may use different trust mechanisms, thepresent invention is in no way dependent upon a particular signaturescheme or trust mechanism.

At the e-mail sender system 30, secure messaging characteristics,message signing in the message 40, may be controlled by messagingsettings. These message settings are either default messaging settingsor a currently selected group of messaging settings established by auser, or possibly custom message settings established by over-ridingdefault or current messaging settings. In known systems, whenever amessage having different message characteristics than those specified ina current group of messaging settings is to be sent from a messagingclient, a different group of messaging settings must be selected orcurrent settings must be over-ridden.

Frequent messaging settings changes are not only tedious and timeconsuming, but are also prone to error. For example, some securemessaging clients may be configured to exchange either secure orunsecure messages with other messaging clients. However, a messagingclient that may not be configured for secure messaging is unable toprocess received secure messages.

As described above, known messaging clients allow only a single group ofmessaging settings to be active at any time. Therefore, when a securemessaging client exchanges messages with unsecure messaging clientsrelatively often, a user of the secure messaging client might normallyselect only general messaging settings as default messaging settings toensure that sent messages may be processed by unsecure messagingclients. Then, when a secure message is to be sent to a secure messagingclient, a different group of settings is selected or the current generalmessaging settings are over-ridden, so that a secure message is sent.When a user forgets to select secure messaging settings or over-ridegeneral messaging settings, a message that was intended to be sentsecurely is sent in the clear. This situation may be particularlyundesirable when such a message contains confidential information, forexample. Similarly, when secure messaging settings are used as defaultsettings and not over-ridden when a message is to be sent to an unsecuremessaging client, the unsecure messaging client will be unable toprocess the secure message and the user must re-transmit the message inan unsecure format.

According to an aspect of mimetic messaging settings selection asdescribed herein, when a message to be sent from a messaging client isrelated to a received message, the messaging client determines themessaging settings used in the received message and selects themessaging settings used in the received message to control messagecharacteristics of the reply message. Such mimetic settings selectioncan reduce the number of times that a user must manually changemessaging settings, and also allows a message sender to establishmessaging settings for an entire “conversation”, including both anoriginal message and any related messages. Related messages are messagesthat include at least a portion of a received message, such as replymessages and forward messages, for example.

FIG. 3 is a block diagram of a wireless mobile communication deviceimplementing a mimetic messaging settings selection system.

The mobile device 38 includes a memory 52, a messaging client 60, a userinterface (UI) 62, and a wireless transceiver 64.

The memory 52 is a writeable store such as a RAM into which other devicecomponents and systems may write data, and includes a storage area for amessage store 54, as well as other data stores such as a Cert store 55,an address book 56 in which messaging contact information is stored, anapplication data storage area 58 which stores data associated withsoftware applications on the mobile device 38, and a settings store 59which stores messaging settings. Data stores 54, 55, 56, 58 and 59 areillustrative examples of stores that may be implemented in a memory 52on mobile device 38. The memory 52 may also be used by other devicesystems in addition to those shown in FIG. 3 to store other types ofdata.

The messaging client 60 is connected to the wireless transceiver 64 andis thus enabled for communications via a wireless network.

The UI 62 may include such UI components as a keyboard or keypad, adisplay, or other components which accept inputs from or provide outputsto a user of the mobile device 38. A mobile device 38 typically includesmore than one UI, and the UI 62 therefore represents one or more userinterfaces.

Messages received by the messaging client 60 via the transceiver 64 arestored in the message store 54. The message store 54 may also be used tostore messages that are sent by the messaging client 60.

The messaging client 60 stores received Certs to the Cert store 55 andretrieves stored Certs from the Cert store 55. Certs are normally storedin the Cert store 55 in the format in which they are received, but mayalternatively be parsed or otherwise translated into a storage formatbefore being written to the Cert store 55. Certs may be received withsecure messages, requested from a Cert source such as a PKS via thewireless transceiver 64, or loaded onto the mobile device 38 through acommunications interface such as a serial port, Universal Serial Bus(USB) port, Infrared Data Association (IrDA) port, Bluetooth™ module, oran 802.11 module, from a similarly equipped external system, a PC forexample. Those skilled in the art will appreciate that “Bluetooth” and“802.11” refer to sets of specifications, available from the Instituteof Electrical and Electronics Engineers (IEEE), relating to personalarea networks and wireless LANs, respectively. As described above, apublic key in a Cert may be required for sending or receiving securemessages.

The address book 56 stores contact information, at least some of whichis preferably used by the messaging client 60 in messaging operations.Entries in an address book 56 are typically most often used foraddressing messages to be sent from a messaging client. Address bookentries are also used to replace addressing information, such as ane-mail address, with a personal or familiar name when a message that isreceived from a sender for which an address book entry exists in theaddress book 56 is displayed to a user of the mobile device 38. Anaddress book entry can typically be created either manually, for exampleby inputting contact information or selecting an address from a receivedmessage using a UI 62, or automatically, such as by configuring themessaging client 60 to store contact information when a message isreceived from a sender for which no entry exists in the address book 56.Contact information could also possibly be extracted and stored in theaddress book 56 when a new Cert is stored to the Cert store 55, asdescribed in the International Patent Application Serial No.PCT/CA03/00406, entitled “Certificate Information Storage System AndMethod”, filed on 20 Mar. 2003, assigned to the assignee of the presentapplication, and incorporated herein by reference.

The settings store 59 stores messaging settings which control thecharacteristics of outgoing messages sent from the mobile device 38. Thesettings store 59 may store more than one group of messaging settings,although in known systems, only one previously selected group ofsettings is active at any time. A typical messaging client determineswhich group of messaging settings was previously selected and uses thosesettings to control the characteristics of an outgoing message.

The messaging client 60, however, is configured to provide for selectionof different messaging settings for different types of outgoing message.This feature may be enabled, for example, for mimetic messaging settingsselection for reply messages. The concept of mimetic messaging settingsselection will be further described below with reference to FIGS. 4 and5.

FIG. 4 is a block diagram showing an exemplary message structure thatsupports mimetic messaging settings selection. Although the examplemessage 70 is a secure message that has been both signed and encrypted,it should be understood that mimetic messaging settings selection may beapplied to other types of secure messages, such as signed-only orencrypted-only messages, or to unsecure messages.

The message 70 includes an address information portion 72, a messagingsettings portion 74, a digital signature-related information portion 76,a message body 78, and one or more encrypted session keys 80. Dependingupon the type of message and the type of messaging client that was usedto generate the message, a message may contain more, fewer or differentfields than those shown in FIG. 4. Normally, a message such as an emailmessage, for example, will include at least an address informationportion 72, some sort of message settings portion 74, and a message body78.

The address information portion 72 includes information which identifiesat least an intended receiver of the message 70. For an email message,address information typically includes “To:”, “From:”, and possibly“Cc:” and “Bcc:” email addresses, although, as those skilled in the artof electronic messaging will appreciate, e-mail message recipients willnot typically see “Bcc:” addresses.

The messaging settings portion 74 preferably includes a group ofmessaging settings that were used to control the characteristics of themessage 70. Messaging settings are usually manually configurable by amessage sender using a messaging client, as described above. Themessaging settings specified in the messaging settings portion 74 maycorrespond to a previously established and saved group of messagesettings stored in a settings store such as 59, for example, selected bya message sender when the message 70 was composed. Alternatively, amessage sender may have chosen a specific “custom” set of messagingsettings for the message 70. Messaging settings may control such generalmessage characteristics as fonts, backgrounds, text size and the like,as well as secure message characteristics, including a digest algorithmfor a signed message and an encryption algorithm for an encryptedmessage, for example.

The digital signature-related information portion 76 includes a digitalsignature, and possibly other signature-related information such as thesender's Cert, a Cr t chain and one or more CRLs. The digitalsignature-related information portion 76 is processed by a messagereceiver as described above to verify the digital signature in themessage 70.

The message body 78 includes the text or information portion of themessage 70. In the message 70, the message body 78 is both signed andencrypted. A message 70 may also include file attachments in orassociated with the message body portion 78. The appearance and types ofprocessing applied to the message body 78 are controlled by themessaging settings indicated in the messaging settings portion 74.

In operation, a message 70 may be composed on the mobile device 38, oron any other device or system on or in conjunction with which amessaging client 60 is operating, using UIs 62 such as a keyboard and adisplay. A messaging client such as 60 is normally able to send newmessages and reply messages, and also forward received messages orportions of received messages. For new messages, as described above, auser may select a group of messaging settings to control messagecharacteristics of the new message. When no messaging settings areselected, a default group of messaging settings typically controls themessage characteristics. Many messaging clients also provide a mechanismto over-ride currently selected or default messaging settings when amessage is being composed.

When an outgoing message that is related to a received message iscomposed using the messaging client 60, however, mimetic messagingsettings selection is preferably used to determine the messagingsettings that should control the characteristics of the outgoingmessage. Outgoing messages related to a received message include suchmessages as reply messages or forward messages, for example, or anyother messages which include at least a portion of the received message.For such messages, the messaging client 60 accesses the message store 54(FIG. 3) to determine the messaging settings associated with messagecharacteristics of the received message. The messaging settingsassociated with the message characteristics of the received message arethen selected to control message characteristics of the outgoingmessage. The messaging client thereby selects or “profiles” themessaging settings or characteristics used for the received message,such that messaging settings used by a message sender establish messagecharacteristics for an entire conversation, including not only anoriginal message, but also any related messages. The messaging settingsportion 74 of the message 70 supports a direct determination ofmessaging settings used by a message sender. However, as described infurther detail below, the invention is in no way restricted to mimeticmessaging settings selection based on direct determination of messagingsettings used for a received message.

As described above, messaging settings may control general messagecharacteristics, such as formats and fonts, as well as secure messagecharacteristics, such as signing and encryption. When the selectedmessaging settings dictate that a secure message is to be sent, themessaging client 60 retrieves any required keys and processes theoutgoing message as specified in the selected messaging settings. Forexample, when the selected messaging settings specify that a signed andthen encrypted S/MIME message is to be sent, then the messaging client60 may use its own private key to generate a digital signature for themessage, generate a session key and use the session key to encrypt themessage and the digital signature, retrieve the public key or Cert foreach message recipient from the Cert store 54, and encrypt the sessionkey with each recipient's public key.

Although certain messaging settings or characteristics, such as securemessaging settings, may be of particular concern to most message sendersusing a mimetic messaging settings selection system, general settingsmay also be important for some messaging clients. For example, a desktopcomputer system may be capable of displaying a message in any of avariety of fonts, whereas a mobile device may have relatively limiteddisplay capabilities. Therefore, a message sender using a messagingclient on a mobile device such as 38 (FIG. 3) may prefer that anoriginal font of a message body be used in any replies to that message,so that reply messages may be displayed properly on the mobile device.

In this example, the message sender might not necessarily wish to ensurethat the same font is used for forward, messages, in which the originalmessage is forwarded to other recipients, but not to the message sender.This type of preference could possibly be specified using one or morecontrol flags, in the messaging settings portion 74 of a message 70, forexample. Such flags could control which messaging settings orcharacteristics are effectively carried forward to messages that arerelated to a received message. Control flags could provide for suchfunctions as specifying that security-related messaging settings shouldbe used for any messages related to a received message, whereasmessaging settings controlling general message characteristics such asfonts or backgrounds should be used for reply messages but not forwardmessages. Thus, for an outgoing message, a messaging client determineswhether the message is related to a received message and may thendetermine a type of the outgoing message. When control flags are used,the messaging client then selects messaging settings for the outgoingmessage in accordance with the type of the message and the controlflags.

It may also be desirable in some circumstances not to preclude the useof default or other messaging settings when a group of messagingsettings is selected through mimetic messaging settings selection. Whenan outgoing message prepared at the messaging client 60 is a forwardmessage, wherein a received message or a portion thereof is to beforwarded to a message recipient, messaging settings used for thereceived message may be selected to control the message characteristicsof the outgoing message, as described above. However, if a user of themessaging client 60 is aware of certain limitations of a messagingclient used by a recipient of the forward message, then the user maywish to change the selected messaging settings or specify furthermessaging settings to allow the forward message to be processed by themessage recipient.

The use of control flags or similar indicators also provides for somemeasure of control over which particular messaging settings used for areceived message may be changed or whether additional messaging settingsmay be used for a an outgoing message related to the received message.For example, an over-ride flag may be set when any of the messagingsettings used for a received message may be over-ridden for an outgoingmessage related to the received message, or reset when none of themessaging settings may be over-ridden. A similar flag, group of flags,or list of messaging settings may indicate which messaging settings orcharacteristics may, or alternatively, may not, be changed for relatedmessages. A further flag may be used to indicate whether additionalmessaging settings may be specified for related messages or certaintypes of related messages.

A messaging settings portion 74 of a received message 70 might alsospecify alternative messaging settings that may be used for an outgoingrelated message instead of particular messaging settings used for thereceived message. For example, a received message 70 could be a signedand encrypted S/MIME message for which the SHA1 hashing algorithm wasused to generate a hash of the message body 78 (and the encryptedsession keys 80 if the message was encrypted and then signed). In orderto provide for some flexibility in regard to messaging settings used bya receiving messaging client for outgoing messages related to thereceived message, the messaging settings portion 74 may specify that adigital signature for a related outgoing message could be generatedusing MD5 instead of SHA1. Thus, when an outgoing related message is tobe sent from the receiving messaging client to another messaging clientwhich supports MD5, but not SHA1, such as a messaging client whichsupports Version 2 of S/MIME, the receiving messaging client may use MD5instead of SHA1 to generate a digital signature for the outgoingmessage. In this example, the receiving messaging client profiles themessaging settings of the received message in that the original messageis signed, and the sender of the received message maintains some levelof control of messaging settings used for any related messages.

When alternative messaging settings are specified in a received message,an order of preference may be explicitly specified in the message, or,for example, inherent in the order in which the alternative messagingsettings are listed in the message. Messaging settings that were usedfor the received message may be preferred over any other messagingsettings, and the alternative messaging settings may be listed in orderof preference. A sender of a received message may also specify differentalternative messaging settings for different types of related messages,such as reply messages and forward-messages. In the above example ofhashing algorithms, if a sending messaging client supports only MD5,then alternative hashing algorithms may be specified for forwardmessages, but not for reply messages.

According to another variation, a messaging client may be configured toallow messaging settings to be established for an outgoing relatedmessage in addition to any messaging settings of a received message thatare to be profiled in the outgoing message. For example, if a receivedmessage is encrypted, then a related outgoing message might be bothencrypted and signed. Even though additional messaging settings may beselected for a related message, certain characteristics of a receivedmessage, encryption in the above example, are profiled in an outgoingrelated message. Such a technique is analogous to logically OR-ingmessaging settings, in that messaging settings for a related message maybe added by a messaging client, but messaging settings of a receivedmessage that are to be profiled in outgoing related messages arepreferably not deselected or over-ridden.

As a further extension of these principles, a received message mightalso or instead specify message characteristics that are to be profiledfor any related messages. Instead of specifying that SHA1 is to be usedto generate a digital signature for related messages, for example, areceived message may specify that any related message is to be signed. Areceiving messaging client is then free to choose a hashing and signingalgorithm. In this case, profiling is performed on the basis of messagecharacteristics, and a messaging client selects appropriate messagingsettings in order to profile the characteristics of a received message.Such message characteristic profiling further extends the flexibility ofmessaging settings selection systems and methods. For example, areceived message that is encrypted and signed using S/MIME may specifyonly that related messages should be encrypted and signed. A receivingmessaging client may then use PGP or another secure messaging scheme toencrypt and sign outgoing related messages. As described above,different messaging settings may be allowed only for certain types ofrelated messages. The control flags, preferences, and other featuresdescribed above in the context of messaging settings are also applicableto message characteristics.

It should be apparent that a sender of a received message need notnecessarily support the same type or format of messaging settings. Wherethe sender and receiver use different types of messaging client, thereceiver preferably selects messaging settings for any outgoing relatedmessages based on a translation or similar interpretation of sender-sidemessaging settings, a set of message characteristics specified in thereceived message, or the actual message characteristics of the receivedmessage. Mimetic messaging settings selection based on actual messagecharacteristics is possible even where a receiving messaging clientcannot correctly interpret messaging settings or characteristicsspecified in a received message.

FIG. 5 is a flow chart illustrating a method of mimetic messagingsettings selection on a messaging client.

The method begins at step 92, when an outgoing message is composed on amessaging client. The messaging client then determines whether theoutgoing message is related to a received message at step 94. Anoutgoing message is a message, such as a reply message or a forwardmessage for example, that includes at least a portion of a receivedmessage. The check at step 94 may be performed, for example, when acompose message operation is initiated, while a message is beingcomposed, or when a user attempts to send a composed message. If theoutgoing message is not related to a received message, then the messageis prepared for transmission, by encoding, signing, encrypting or otherprocessing, in accordance with default or selected messaging settings,and sent to each recipient at step 102.

Where the outgoing message is related to a received message, themessaging client determines the messaging settings associated withmessage characteristics of the received message, at step 98, and selectssuch messaging settings to control message characteristics of theoutgoing message. As described above, the messaging settings associatedwith message characteristics of a received message may be determined byaccessing a message store, for example. At step 100, the messagingclient determines whether a user of the messaging client, or possiblythe messaging client itself, is attempting to over-ride or change any ofthe selected messaging settings. If not, then the outgoing message isprepared for sending by performing processing operations in accordancewith the selected messaging settings and sent to each message recipientat step 102.

If the messaging settings are over-ridden or changed, either by changingone or more messaging settings or by specifying additional messagingsettings to be used, the messaging client preferably determines whetherthe over-rides or changes are allowed, at step 104, for example bychecking control flags, alternative settings or characteristics lists,and the like, in the received message. Where the over-rides or changesare allowed, the message is prepared according to the over-ridden orchanged messaging settings and sent to each recipient at step 102.Otherwise, the messaging client may display an alert or error messageand/or prompt the user for further input at step 106. In somecircumstances, the outgoing message may possibly be sent without themessaging settings over-rides or changes, if the message recipients areable to process the outgoing message with the messaging settings usedfor the received message, for example. A user may then choose to sendthe outgoing message without the message settings over-rides or changes,as determined at step 108, and the message is prepared and sent at step102. If the user chooses not to send the outgoing message without themessaging settings over-rides or changes, then message processing may beaborted at step 110. Other error or exception processing may also beinvoked if an outgoing message cannot be sent without messaging settingsover-rides or changes or a user chooses not to send an outgoing messagewithout messaging settings over-rides or changes.

As described above for step 94, step 100 and the steps related theretomay be performed when a compose message function is started, duringmessage composition, or when a user attempts to send a composed message.

FIG. 6 is a block diagram of a wireless mobile communication device. Themobile device 600 is preferably a dual-mode, two-way communicationdevice having at least voice and data communication capabilities. Thedevice preferably has the capability to communicate with other computersystems on the Internet. Depending on the functionality provided by themobile device 600, the mobile device may be referred to as a datamessaging device, a two-way pager, a cellular telephone with datamessaging capabilities, a wireless Internet appliance or a datacommunication device (with or without telephony capabilities).

The mobile device 600 includes a transceiver 611, a microprocessor 638,a display 622, Flash memory 624, random access memory (RAM) 626,auxiliary input/output (I/O) devices 628, a serial port 630, a keyboard632, a speaker 634, a microphone 636, a short-range wirelesscommunications sub-system 640, and other device sub-systems 642. Thetransceiver 611 preferably includes transmit and receive antennas616,618, a receiver (Rx) 612, a transmitter (Tx) 614, one or more localoscillators (LOs) 613, and a digital signal processor (DSP) 620. Withinthe Flash memory 624, the mobile device 600 includes a plurality ofsoftware modules 624A-624N that can be executed by the microprocessor638 (and/or the DSP 620), including a voice communication module 624A, adata communication module 624B, and a plurality of other operationalmodules 624N for carrying out a plurality of other functions.

As described above, the mobile device 600 is preferably a two-waycommunication device having voice and data communication capabilities.Thus, for example, the mobile device 600 may communicate over a voicenetwork, such as any of the analog or digital cellular networks, and mayalso communicate over a data network. The voice and data networks aredepicted in FIG. 6 by the communication tower 619. These voice and datanetworks may be separate communication networks using separateinfrastructure, such as base stations, network controllers, etc., orthey may be integrated into a single wireless network.

The communication subsystem 611 is used to communicate with the network619. The DSP 620 is used to send and receive communication signals toand from the transmitter 614 and receiver 612, and also exchangescontrol information with the transmitter 614 and receiver 612. If thevoice and data communications occur at a single frequency, orclosely-spaced set of frequencies, then a single LO 613 may be used inconjunction with the transmitter 614 and receiver 612. Alternatively, ifdifferent frequencies are utilized for voice communications versus datacommunications, then a plurality of LOs 613 can be used to generate aplurality of frequencies corresponding to the network 619. Although twoantennas 616, 618 are depicted in FIG. 6, the mobile device 600 could beused with a single antenna structure. Information, which includes bothvoice and data information, is communicated to and from thecommunication module 611 via a link between the DSP 620 and themicroprocessor 638.

The detailed design of the communication subsystem 611, such asfrequency band, component selection, power level, etc., is dependentupon the communication network 619 in which the mobile device 600 isintended to operate. For example, a mobile device 600 intended tooperate in a North American market may include a communication subsystem611 designed to operate with the Mobitex or DataTAC mobile datacommunication networks and also any of a variety of voice communicationnetworks, such as AMPS, TDMA, CDMA, PCS, etc., whereas a mobile device600 intended for use in Europe may be configured to operate with theGPRS data communication network and the GSM voice communication network.Other types of data and voice networks, both separate and integrated,may also be utilized with the mobile device 600.

Depending upon the type of network 619, the access requirements for thedual-mode mobile device 600 may also vary. For example, in the Mobitexand DataTAC data networks, mobile devices are registered on the networkusing a unique identification number associated with each device. InGPRS data networks, however, network access is associated with asubscriber or user of a mobile device 600. A GPRS device typicallyrequires a subscriber identity module (“SIM”), which is required inorder to operate the mobile device 600 on a GPRS network. Local ornon-network communication functions (if any) may be operable, withoutthe SIM, but the mobile device 600 will be unable to carry out anyfunctions involving communications over the network 619, other than anylegally required operations, such as ‘911’ emergency calling.

After any required network registration or activation procedures havebeen completed, the mobile device 600 may send and receive communicationsignals, preferably including both voice and data signals, over thenetwork 619. Signals received by the antenna 616 from the communicationnetwork 619 are routed to the receiver 612, which provides for signalamplification, frequency down conversion, filtering, channel selection,etc., and analog to digital conversion. Analog to digital conversion ofthe received signal allows more complex communication functions, such asdigital demodulation and decoding to be performed using the DSP 620. Ina similar manner, signals to be transmitted to the network 619 areprocessed, including modulation and encoding, for example, by the DSP620 and are then provided to the transmitter 614 for digital to analogconversion, frequency up conversion, filtering, amplification andtransmission to the communication network 619 via the antenna 618.Although a single transceiver 611 is shown in FIG. 6 for both voice anddata communications, the mobile device 600 may include more than onedistinct transceivers, such as a first transceiver for transmitting andreceiving voice signals, and a second transceiver for transmitting andreceiving data signals.

In addition to processing the communication signals, the DSP 620 alsoprovides for receiver and transmitter control. For example, the gainlevels applied to communication signals in the receiver 612 andtransmitter 614 may be adaptively controlled through automatic gaincontrol algorithms implemented in the DSP 620. Other transceiver controlalgorithms could also be implemented in the DSP 620 in order to providemore sophisticated control of the transceiver 611.

The microprocessor 638 preferably manages and controls the overalloperation of the mobile device 600. Many types of microprocessors ormicrocontrollers could be used for this part, or, alternatively, asingle DSP 620 could be used to carry out the functions of themicroprocessor 638. Low-level communication functions, including atleast data and voice communications, are performed through the DSP 620in the transceiver 611. Other, high-level communication applications,such as a voice communication application 624A, and a data communicationapplication 624B may be stored in the Flash memory 624 for execution bythe microprocessor 638. For example, the voice communication module 624Amay provide a high-level user interface operable to transmit and receivevoice calls between the mobile device 600 and a plurality of other voicedevices via the network 619. Similarly, the data communication module624B may provide a high-level user interface operable for sending andreceiving data, such as e-mail messages, files, organizer information,short text messages, etc., between the mobile device 600 and a pluralityof other data devices via the network 619. On the mobile device 600, amessaging software application may operate in conjunction with the datacommunication module 624B in order to implement the techniques describedabove.

The microprocessor 638 also interacts with other device subsystems, suchas the display 622, Flash memory 624, RAM 626, auxiliary input/output(I/O) subsystems 628, serial port 630, keyboard 632, speaker 634,microphone 636, a short-range communications subsystem 640 and any otherdevice subsystems generally designated as 642. The components 628, 632,634 and 636 are examples of the types of subsystems that could beprovided as UIs 62 (FIG. 3). The modules 624A-N are executed by themicroprocessor 638 and may provide a high-level interface between a userof the mobile device and the mobile device. This interface typicallyincludes a graphical component provided through the display 622, and aninput/output component provided through the auxiliary I/O 628, keyboard632, speaker 634, or microphone 636.

Some of the subsystems shown in FIG. 6 perform communication-relatedfunctions, whereas other subsystems may provide “resident” or on-devicefunctions. Notably, some subsystems, such as keyboard 632 and display622 may be used for both communication-related functions, such asentering a text message for transmission over a data communicationnetwork, and device-resident functions such as a calculator or task listor other PDA type functions.

Operating system software used by the microprocessor 638 is preferablystored in a non-volatile store such as Flash memory 624. As thoseskilled in the art will appreciate, the Flash memory 624 is one type ofnon-volatile store, which could instead be implemented as a batterybacked-up RAM, for example. In addition to the operating system andcommunication modules 624A-N, the Flash memory 624 may also include afile system for storing data. A storage area is also preferably providedin the Flash memory 624 to store received and possibly sent messages, aswell as public keys, a private key, and other information that may berequired for secure messaging. The operating system, specific deviceapplications or modules, or parts thereof, may be temporarily loadedinto a volatile store, such as RAM 626 for faster operation. Moreover,received communication signals may also be temporarily stored to RAM 626before permanently writing them to a file system located in thepersistent store 624.

An exemplary application module 624N that may be loaded onto thedual-mode device 100 is a personal information manager (PIM) applicationproviding PDA functionality, such as calendar events, appointments, andtask items. This module 624N may also interact with the voicecommunication module 624A for managing phone calls, voice mails, etc.,and may also interact with the data communication module 624B formanaging e-mail communications and other data transmissions.Alternatively, all of the functionality of the voice communicationmodule 624A and the data communication module 624B may be integratedinto the PIM module.

The Flash memory 624 preferably provides a file system to facilitatestorage of PIM data items on the device. The PIM application preferablyincludes the ability to send and receive data items, either by itself,or in conjunction with the voice and data communication modules 624A,624B, via the wireless network 619. The PIM data items are preferablyseamlessly integrated, synchronized and updated, via the wirelessnetwork 619, with a corresponding set of data items stored or associatedwith a host computer system, thereby creating a mirrored system for dataitems associated with a particular user.

The mobile device 600 may also be manually synchronized with a hostsystem by placing the mobile device 600 in an interface cradle, whichcouples the serial port 630 of the mobile device 600 to the serial portof the host system. The serial port 630 may also be used to enable auser to establish messaging settings through an external device orsoftware application, to download other application modules 624N forinstallation, and to load Certs, keys and other information onto adevice. This wired download path may be used to load an encryption keyonto the device, which is a more secure method than exchangingencryption information via the wireless network 619. In a similarmanner, other types of wired interfaces such as a Universal Serial Bus(USB) port could be implemented in the mobile device 600 in addition toor instead of the serial port 630.

Additional application modules 624N may be loaded onto the mobile device600 through the network 619, through an auxiliary I/O subsystem 628,through the serial port 630, through the short-range communicationssubsystem 640, or through any other suitable subsystem 642, andinstalled by a user in the Flash memory 624 or RAM 626.

Such flexibility in application installation increases the functionalityof the mobile device 600 and may provide enhanced on-device functions,communication-related functions, or both. For example, securecommunication applications may enable electronic commerce functions andother such financial transactions to be performed using the mobiledevice 600.

When the mobile device 600 is operating in a data communication mode, areceived signal, such as a text message or a web page download, will beprocessed by the transceiver 611 and provided to the microprocessor 638,which will preferably further process the received signal for output tothe display 622, or, alternatively, to an auxiliary I/O device 628. Auser of mobile device 600 may also compose data items, such as emailmessages, using the keyboard 632, which is preferably a completealphanumeric keyboard laid out in the QWERTY style, although otherstyles of complete alphanumeric keyboards such as the known DVORAK stylemay also be used. User input to the mobile device 600 is furtherenhanced with a plurality of auxiliary I/O devices 628, which mayinclude a thumbwheel input device, a touchpad, a variety of switches, arocker input switch, etc. The composed data items input by the user maythen be prepared as specified in selected messaging settings andtransmitted over the communication network 619 via the transceiver 611.

When the mobile device 600 is operating in a voice communication mode,the overall operation of the mobile device 600 is substantially similarto the data mode, except that received signals are preferably output tothe speaker 634 and voice signals for transmission are generated by amicrophone 636. Alternative voice or audio I/O subsystems, such as avoice message recording subsystem, may also be implemented on the mobiledevice 600. Although voice or audio signal output is preferablyaccomplished primarily through the speaker 634, the display 622 may alsobe used to provide an indication of the identity of a calling party, theduration of a voice call, or other voice call related information. Forexample, the microprocessor 638, in conjunction with the voicecommunication module 624A and the operating system software, may detectthe caller identification information of an incoming voice call anddisplay it on the display 622.

A short-range communications subsystem 640 may include an infrareddevice and associated circuits and components, or a short-range RFcommunication module such as a Bluetooth module or an 802.11 module toprovide for communication with similarly-enabled systems and devices.

The above description relates to examples of the present invention. Manyvariations will be apparent to those knowledgeable in the field, andsuch variations are within the scope of the invention as described andclaimed, whether or not expressly described.

For example, although a wireless mobile communication device is shown inFIGS. 3 and 6 and represents one possible type of device on or inconjunction with which a messaging client may operate, the invention mayalso be implemented in other systems supporting messaging clients,including desktop and laptop computer systems, networked computersystems and other types of systems.

Furthermore, the systems and methods described herein may be applied tomessages which include only a portion of a received message, not only toforward and reply messages, which typically include an entire message.When any content from a message, including any message attachments, isincorporated into an outgoing message by a copy and paste operation, forexample, the outgoing message preferably profiles messaging settingsassociated with message characteristics of the message from which thecontent was copied. In one possible embodiment, when any content from amessage is copied to a clipboard or other temporary store, the messagingsettings or characteristics associated with the message or a messageidentifier used to access the message may also be selected and copied tothe clipboard with the copied content, or otherwise linked with thecopied content. When the copied content is pasted into an outgoingmessage, then messaging settings associated with characteristics of themessage from which the content was copied are selected for the outgoingmessage. According to another possible implementation, when any part ofa received message is displayed or otherwise accessed in such a way asto permit copying of content from the received message, the messagingsettings associated with message characteristics of the received messageare selected and used for any outgoing message into which parts of thereceived message may be copied. Similarly, a messaging client may beconfigured such that messaging settings related to a received messageremain active for any outgoing message until the received messagecontent is no longer available for copying, such as when the receivedmessage is closed or a clipboard or other temporary store is cleared,for example.

Messaging settings conflicts that may arise for outgoing messages thatare related to more than one previous message may be resolved in avariety of ways. Settings conflicts may occur, for example, when aportion of a first received message with a first group of messagingsettings or characteristics is copied into a reply message to a secondreceived message with a second group of messaging settings orcharacteristics. A simple conflict resolution scheme involveseffectively OR-ing the first and second groups of messaging settings orcharacteristics, substantially as described above for messaging settingsover-riding. The resultant group of messaging settings orcharacteristics thereby includes messaging settings or characteristicscorresponding to those in each of the first and second groups. Wherecontrol flags are used for one or both of the first and second messages,the first and second groups may be combined and/or changed in accordancewith the flags. A messaging client may instead be configured to select amost secure group of messaging settings or characteristics betweenmultiple groups. Other conflict resolution schemes may also be apparentto those skilled in the art and, as such, are considered to be withinthe scope of the systems and methods described herein.

In addition, control flags or similar control information need notnecessarily be stored in a message store with a received message asdescribed above. This type of control information could instead bestored in a different store or memory than a received message. Where thedifferent store or memory is indexed by a message identifier, amessaging client locates corresponding messaging settings in thedifferent store or memory using a message identifier for a receivedmessage to which an outgoing message is related.

Messaging settings profiling has been described above primarily in thecontext of outgoing messages that are related to received messages.However, similar techniques may be applied when an outgoing message isrelated to other types of messages, such as when a saved or previouslysent message is to be re-sent or forwarded.

It is also contemplated that a greater degree of control over outgoingmessages related to a received message could be provided to a sender ofthe received message. Message permissions or restrictions may beestablished by the message sender to control how a message is handled orprocessed at a receiving messaging client. Permissions or restrictionsmay control, for example, whether the message may be forwarded or sentto other recipients, to whom a message may be forwarded, how the messagemay be forwarded, and the like. In such a system, a recipient messagingclient may be configured to contact the sender of a received messagewhere a restricted operation is being attempted on the received message.This functionality supports sender auditing of whether and how oftenrecipients attempt to perform restricted operations on messages itsends, and may also provide a mechanism for a sender to providepermissions to over-ride a message restriction on a per message and asrequired basis. Restricted operations may then proceed where the senderprovides appropriate permission. The sender may thereby maintainultimate control over any message restriction over-rides.

INDUSTRIAL APPLICABILITY

The invention relates generally to the field of electronic messaging,and in particular to selecting messaging settings to control messagecharacteristics on a messaging client.

1. A method of mimetic message settings selection on a messaging client,comprising the steps of: detecting an outgoing message; determiningwhether the outgoing message is related to a previously receivedmessage, the received message having message characteristics;determining messaging settings associated with the messagecharacteristics of the received message where the outgoing message isrelated to a previously received message; and selecting the messagingsettings associated with the message characteristics of the receivedmessage to control message characteristics of the outgoing message. 2.The method of claim 1, wherein the step of determining whether theoutgoing message is related to a previously received message comprisesthe step of determining whether the outgoing message includes a portionof a previously received message.
 3. The method of claim 2, wherein thereceived message comprises an attachment, and wherein the step ofdetermining whether the outgoing message includes a portion of apreviously received message comprises the step of determining whetherthe outgoing message includes the attachment.
 4. The method of claim 1,wherein the step of determining whether the outgoing message is relatedto a previously received message comprises the step of determiningwhether the outgoing message is a reply to a previously receivedmessage.
 5. The method of claim 1, wherein the step of determiningwhether the outgoing message is related to a previously received messagecomprises the step of determining whether the outgoing message is aforward message incorporating a previously received message.
 6. Themethod of claim 1, wherein the step of determining messaging settingscomprises the steps of: analyzing the received message to determine themessage characteristics; and determining messaging settings that controlthe message characteristics.
 7. The method of claim 1, wherein themessage characteristics are specified in the received message, andwherein the step of determining messaging settings comprises the stepsof: accessing the specified message characteristics; and determiningmessaging settings that control the specified message characteristics.8. The method of claim 1, wherein the received message comprises amessaging settings field specifying messaging settings used for thereceived message, and wherein the step of determining messaging settingscomprises the step of accessing the messaging settings field in thereceived message.
 9. The method of claim 8, wherein the received messagefurther comprises messaging settings control flags, and wherein the stepof selecting comprises the step of selecting messaging settings based onthe control flags.
 10. The method of claim 9, wherein the control flagsindicate which of the messaging settings specified in the messagingsettings field must be selected for the outgoing message.
 11. The methodof claim 1, wherein the message characteristics of the received messagecomprise required message characteristics, and the step of selectingcomprises the step of confirming that messaging settings associated withthe required message characteristics are selected.
 12. The method ofclaim 11, further comprising the step of alerting a user where messagingsettings associated with the required message characteristics are notselected.
 13. The method of claim 1, wherein the message characteristicsof the received message comprise required message characteristics,further comprising the steps of: receiving an input from a user of themessaging client; determining whether the input changes any of therequired message characteristics; and alerting the user where the inputchanges any of the required message characteristics.
 14. The method ofclaim 13, wherein the input specifies further messaging settings inaddition to the messaging settings associated with the required messagecharacteristics, further comprising the step of: selecting the furthermessaging settings in addition to the messaging settings associated withthe required message characteristics to control the messagecharacteristics of the outgoing message.
 15. The method of claim 13,further comprising the step of: ignoring the input where the inputchanges any of the required message characteristics.
 16. The method ofclaim 13, wherein the received message comprises control flagsindicating the required message characteristics.
 17. The method of claim13, wherein the message characteristics of the received message furthercomprise optional message characteristics.
 18. The method of claim 17,wherein the received message comprises control flags indicating therequired message characteristics and the optional messagecharacteristics.
 19. The method of claim 8, wherein the message settingsfield further specifies alternative messaging settings that may be usedfor the outgoing message instead of the messaging settings used for thereceived message, and wherein the step of selecting comprises selecting,for each message setting used for the received message, either themessage setting used for the received message or an alternativemessaging setting.
 20. The method of claim 19, wherein the alternativemessaging settings are specified in order of preference.
 21. The methodof claim 1, wherein the message characteristics of the received messagecomprise a message characteristic associated with a plurality ofmessaging settings, and wherein the step of selecting the messagingsettings comprises the step of selecting one of the plurality ofmessaging settings.
 22. The method of claim 1, wherein the steps ofdetermining messaging settings and selecting the messaging settings arerepeated for each received message to which the outgoing message isrelated.
 23. The method of claim 22, wherein the outgoing message isrelated to a first received message having first message characteristicsand a second received message having second message characteristics, andwherein the step of selecting the messaging settings associated with themessage characteristics of the received message further comprises thesteps of: determining whether the first and second messagecharacteristics include conflicting message characteristics; andselecting messaging settings associated with the first and secondmessage characteristics where the first and second messagecharacteristics do not include conflicting message characteristics. 24.The method of claim 22, wherein the outgoing message is related to afirst received message having first message characteristics and a secondreceived message having second message characteristics, and wherein thestep of selecting the messaging settings associated with the messagecharacteristics of the received message further comprises the steps of:determining whether messaging settings associated with the first andsecond message characteristics include conflicting messaging settings;and selecting the messaging settings associated with the first andsecond message characteristics where the messaging settings associatedwith the first and second message characteristics do not includeconflicting messaging settings.
 25. The method of claim 23, wherein thestep of selecting the messaging settings associated with the messagecharacteristics of the received message further comprising the step of:resolving conflicting message characteristics where the first and secondmessage characteristics include conflicting message characteristics. 26.The method of claim 24, wherein the step of selecting the messagingsettings associated with the message characteristics of the receivedmessage further comprises the step of: resolving conflicting messagingsettings where the messaging settings associated with the first andsecond message characteristics include conflicting messaging settings.27. The method of claim 26, wherein the step of resolving theconflicting messaging settings comprises selecting most secure messagingsettings among the conflicting messaging settings.
 28. The method ofclaim 26, wherein the step of resolving the conflicting messagingsettings comprises the steps of: alerting a user of the messaging clientto the conflicting messaging settings; and prompting the user to choosewhich of the conflicting messaging settings should be selected.
 29. Themethod of claim 1, further comprising the steps of: determining whetherthe received message comprises message restrictions established by amessage sender where the outgoing message is related to a previouslyreceived message; determining whether processing of the outgoing messageis allowed by the message restrictions where the received messagecomprises message restrictions; and processing the outgoing message inaccordance with the selected messaging settings where processing of theoutgoing message is allowed by the message restrictions.
 30. The methodof claim 29, further comprising the step of: contacting the messagesender where the received message comprises message restrictions
 31. Themethod of claim 29, further comprising the steps of: contacting themessage sender to request permission to process the outgoing messagewhere processing of the outgoing message is not allowed by the messagerestrictions; and processing the outgoing message in accordance with theselected messaging settings where a response comprising permission toprocess the outgoing message is received from the message sender. 32.The method of claim 31, wherein the response further comprises anindication of required messaging settings to be used in the processingof the outgoing message.
 33. The method of claim 1, wherein the messagecharacteristics of the received message comprise one or morecharacteristics selected from the group consisting of: message format,message font, common message text, message signing, and messageencryption.
 34. The method of claim 33, wherein the message signing andthe message encryption are signing and encryption according to SecureMultipurpose Internet Mail Extensions (S/MIME).
 35. The method of claim33, wherein the message signing and the message encryption are signingand encryption according to Pretty Good Privacy (PGP).
 36. The method ofclaim 1, wherein the messaging client operates on a wireless mobilecommunication device.
 37. The method of claim 1, wherein the messagingclient operates on a personal computer system.
 38. The method of claim1, further comprising the step of selecting default messaging settingsto control message characteristics of the outgoing message where theoutgoing message is not related to a previously received message.
 39. Asystem of mimetic messaging settings selection comprising: a messagestore configured to store messages having message characteristics; and amessaging client configured to determine whether an outgoing message tobe sent by the messaging client is related to a message in the messagestore, to determine messaging settings associated with the messagecharacteristics of the message in the message store where the outgoingmessage is related to a message in the message store, and to select themessaging settings associated with the message characteristics of themessage in the message store to control message characteristics of theoutgoing message.
 40. The system of claim 39, wherein the message storeis configured to store messages received by the messaging client andmessages sent by the messaging client.
 41. The system of claim 40,wherein the messaging client is further configured to determine whetherthe outgoing message is related to any of the messages received by themessaging client.
 42. The system of claim 40, wherein the messages inthe message store include a message comprising a messaging settingsfield specifying messaging settings used to control the messagecharacteristics of the message.
 43. The system of claim 42, wherein themessaging client is further configured to select the messaging settingsspecified in the messaging settings field of the message in the messagestore to which the outgoing message is related.
 44. The system of claim40, further comprising a messaging settings store specifying messagingsettings used to control the message characteristics of messages in themessage store.
 45. The system of claim 44, wherein the message store andthe messaging settings store are indexed by message identifiers.
 46. Thesystem of claim 44, wherein the messaging client is further configuredto access the messaging settings store, and to select the messagingsettings specified in the messaging settings store for the message inthe message store to which the outgoing message is related.
 47. Thesystem of claim 39, wherein the system is implemented in a deviceselected from the group consisting of: a personal computer system, ahandheld electronic device, a wireless mobile communication device, amobile telephone having data communication functionality, a two-waypager, a voice communication device, a data communication device, and adual-mode communication device.
 48. The system of claim 39, wherein themessage characteristics of the messages in the message store comprisesecure messaging characteristics selected from the group consisting of:message signing and message encryption.